Method and device for relay transmission and relay terminal apparatus

ABSTRACT

Disclosed in the present invention are a method and device for relay transmission, and relay terminal apparatus, used to lower processing complexity of relay transmission. The method comprises: a relay terminal apparatus sends to a core network apparatus a bearer establishment request used to request for establishing an EPS bearer for a remote terminal apparatus; and the relay terminal apparatus receives a reconfiguration message sent by an access network apparatus, the reconfiguration message carrying configuration information of the EPS bearer established for the remote terminal apparatus, wherein the EPS bearer comprises a cellular data transmission channel between the access network apparatus and the relay terminal apparatus, and a D 2 D data transmission channel between the relay terminal apparatus and the remote terminal apparatus.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/067,723, filed on Jul. 2, 2018, which is a US national phaseapplication based upon an International Application No.PCT/CN2016/077919, filed on Mar. 30, 2016. The entire contents of theabove applications are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

Embodiments of the disclosure relate to the field of communications, andmore specifically, to a method and an apparatus for relay transmissionand a relay terminal device.

BACKGROUND

A Device-to-Device (D2D) technology enables neighboring terminal devicesto transmit data by direct links within a close range, instead offorwarding data via an access network equipment. D2D communication and acellular system may share licensed band resources to form a unifiedhybrid cellular-D2D network. In this hybrid network, a part of terminaldevices can still work in a cellular communication mode, that is,communicate with other terminal devices through an access networkequipment, and a part of terminal devices can work in a D2Dcommunication mode, that is, directly transmit data with other terminaldevices through direct links between the terminal devices and the otherterminal devices.

Moreover, a D2D relay can be used to assist data transmission between anaccess network equipment and a terminal device. In this case, the D2Drelay and the D2D terminal adopt a D2D communication mode, and the D2Drelay and the access network equipment adopt a cellular communicationmode. The D2D relay receives and forwards data in a half-duplex mode,and changes its mode during the receiving and forwarding process.

In the related technology, an Evolved Packet System (EPS) bearer is setup between a D2D relay and a cellular network, and a D2D terminal isinvisible to the cellular network. In this case, the D2D relay needs toperform Internet Protocol (IP) Network (NET) traversal when relayingdata transmitted between the D2D terminal and the cellular network, andthe process is rather complex.

SUMMARY

Embodiments of the disclosure provide a method and apparatus for relaytransmission and a relay terminal device, which can reduce theprocessing complexity of relay transmission.

In a first aspect, a method for relay transmission is provided, whichincludes: transmitting, by a relay terminal device, a bearer setuprequest to a core network equipment, the bearer setup request beingconfigured to request the setup of an Evolved Packet System (EPS) bearerfor a remote terminal device; and receiving, by the relay terminaldevice, a reconfiguration message sent by an access network equipment,the reconfiguration message carrying configuration information of theEPS bearer set up for the remote terminal device, where the EPS bearerincludes a cellular data transmission channel between the access networkequipment and the relay terminal device and a Device-to-Device (D2D)data transmission channel between the relay terminal device and theremote terminal device.

According to the method for relay transmission provided by theembodiment of the disclosure, the relay terminal device transmits abearer setup request to the core network equipment, the bearer setuprequest being configured to request the setup of an EPS bearer for theremote terminal device; and the core network equipment and the accessnetwork equipment set up an EPS bearer for the remote terminal deviceaccording to the bearer setup request, where the EPS bearer includes acellular data transmission channel between the access network equipmentand the relay terminal device and a D2D data transmission channelbetween the relay terminal device and the remote terminal device.Therefore, the relay terminal device can adopt the EPS bearer to relaydata transmitted between the remote terminal device and the accessnetwork equipment, such that the relay terminal device can relay indifferent manners and does not need to perform NET traversal, thusreducing the data processing complexity of relay transmission.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

In a first possible implementation of the first aspect, theconfiguration information of the EPS bearer includes configurationinformation of a cellular communication interface between the relayterminal device and the access network equipment and configurationinformation of a D2D communication interface between the relay terminaldevice and the remote terminal device. The configuration information ofthe cellular communication interface is specifically first configurationinformation of a physical layer, and the configuration information ofthe D2D communication interface is specifically second configurationinformation of the physical layer; or, the configuration information ofthe cellular communication interface is specifically first configurationinformation of a physical layer and first configuration information of aLayer 2, and the configuration information of the D2D communicationinterface is specifically at least one of second configurationinformation of the physical layer or second configuration information ofthe Layer 2.

Optionally, the configuration information of the cellular communicationinterface between the relay terminal device and the access networkequipment may be specifically configuration information of a user-planepeer layer between the access network equipment and the relay terminaldevice, and the configuration information of the D2D communicationinterface between the relay terminal device and the remote terminaldevice may be specifically configuration information of a user-planepeer layer between the relay terminal device and the remote terminaldevice.

In view of the above possible implementation, in a second possibleimplementation of the first aspect, the first configuration informationof the physical layer includes at least one of: information of a firsttransmission resource for relay transmission on the cellularcommunication interface, a relay-specific Radio Network TemporaryIdentity (RNTI), a correspondence between a data volume interval forrelay transmission and a Physical Uplink Control Channel (PUCCH)resource, or a correspondence between the data volume interval for relaytransmission and a preamble, where the relay-specific RNTI is used bythe access network equipment to scramble a Physical Downlink ControlChannel (PDCCH) for scheduling downlink data transmission of the remoteterminal device; and the second configuration information of thephysical layer includes: information of a second transmission resourcefor relay transmission on the D2D communication interface.

In view of the above possible implementations, in a third possibleimplementation of the first aspect, the first configuration informationof the Layer 2 includes at least one of: a relay-specific LogicalChannel Identifier (LCID) and a Layer-2 identifier allocated to theremote terminal device, the relay-specific LCID being used foridentifying relay transmission; and/or the second configurationinformation of the Layer 2 includes: the Layer-2 identifier allocated tothe remote terminal device.

In view of the above possible implementations, in a fourth possibleimplementation of the first aspect, the configuration information of theEPS bearer further includes configuration information of a user-planepeer layer between the access network equipment and the remote terminaldevice. The method may further include: transmitting, to the remoteterminal device, the configuration information of the user-plane peerlayer between the access network equipment and the remote terminaldevice.

In view of the above possible implementations, in a fifth possibleimplementation of the first aspect, before the transmitting, by a relayterminal device, a bearer setup request to a core network equipment, themethod may further include: receiving, by the relay terminal device, aconnection setup request from the remote terminal device, the connectionsetup request being configured to request the setup of a D2Dcommunication link between the relay terminal device and the remoteterminal device. The transmitting, by a relay terminal device, a bearersetup request to a core network equipment includes: transmitting, by therelay terminal device, a bearer setup request to the core networkequipment according to the connection setup request.

In view of the above possible implementations, in a sixth possibleimplementation of the first aspect, the transmitting, by a relayterminal device, a bearer setup request to a core network equipmentincludes: transmitting, by the relay terminal device, a Non AccessStratum (NAS) message to the core network equipment, the NAS messageresponding to the bearer setup request.

In view of the above possible implementations, in a seventh possibleimplementation of the first aspect, the bearer setup request carries theterminal device identifier of the remote terminal device; and the EPSbearer is set up by the core network equipment in a manner oftransmitting application layer protocol signaling to the access networkequipment, the application layer protocol signaling carrying theterminal device identifier of the remote terminal device.

Optionally, the core network equipment may be a Mobility ManagementEntity (MME), and in this case, the MME may transmit the applicationlayer protocol signaling to the access network equipment through an S1interface between the MME and the access network equipment.

In view of the above possible implementations, in an eighth possibleimplementation of the first aspect, the transmitting, by a relayterminal device, a bearer setup request to a core network equipmentincludes: transmitting, by the relay terminal device, a Radio ResourceControl (RRC) message to the access network equipment, the RRC messagecarrying the bearer setup request, such that the access networkequipment transmits, to the core network equipment according to the RRCmessage, application layer protocol signaling for requesting the setupof a bearer for the remote terminal device.

Optionally, the application layer protocol signaling sent by the accessnetwork equipment to the core network equipment may carry the bearersetup request, such that the core network equipment sets up an EPSbearer for the remote terminal device according to identificationinformation of the remote terminal device carried in the bearer setuprequest.

In view of the above possible implementations, in a ninth possibleimplementation of the first aspect, the bearer setup request is furtherconfigured to request the setup of a Packet Data Network (PDN)connection for the remote terminal device; and the reconfigurationmessage further carries configuration information of the PDN connectionset up for the remote terminal device. The method may further include:transmitting, by the relay terminal device, the configurationinformation of the PDN connection to the remote terminal device.

In a second aspect, another method for relay transmission is provided,which includes: receiving, by a core network equipment, a bearer setuprequest sent by a relay terminal device, the bearer setup request beingconfigured to request the setup of an EPS bearer for a remote terminaldevice; and setting up, by the core network equipment, an EPS bearer forthe remote terminal device according to the bearer setup request, wherethe EPS bearer includes a cellular data transmission channel between theaccess network equipment and the relay terminal device and a D2D datatransmission channel between the relay terminal device and the remoteterminal device.

In a first possible implementation of the second aspect, the bearersetup request carries a terminal device identifier of the remoteterminal device.

In view of the above possible implementation, in a second possibleimplementation of the second aspect, the receiving, by a core networkequipment, a bearer setup request sent by a relay terminal deviceincludes: receiving, by the core network equipment, a NAS message sentby the relay terminal device, the NAS message responding to the bearersetup request; and the setting up, by the core network equipment, an EPSbearer for the remote terminal device according to the bearer setuprequest includes: transmitting, by the core network equipment,application layer protocol signaling to the access network equipment,the application layer protocol signaling carrying the terminal deviceidentifier of the remote terminal device.

Optionally, the application layer protocol signaling carries the bearersetup request.

In view of the above possible implementations, in a third possibleimplementation of the second aspect, the receiving, by a core networkequipment, a bearer setup request sent by a relay terminal deviceincludes: receiving, by the core network equipment, application layerprotocol signaling sent by the access network equipment, where theapplication layer protocol signaling is sent by the access networkequipment according to an RRC message sent by the relay terminal device,and the RRC message carries the bearer setup request.

In a third aspect, another method for relay transmission is provided,which includes: receiving, by an access network equipment, a bearersetup request for requesting the setup of an EPS bearer for a remoteterminal device; setting up, by the access network equipment, an EPSbearer for the remote terminal device according to the bearer setuprequest, where the EPS bearer includes a cellular data transmissionchannel between the access network equipment and a relay terminal deviceand a D2D data transmission channel between the relay terminal deviceand the remote terminal device; and transmitting, by the access networkequipment, a reconfiguration message to the relay terminal device, thereconfiguration message carrying configuration information of the EPSbearer.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

In a first possible implementation of the third aspect, theconfiguration information of the EPS bearer includes configurationinformation of a cellular communication interface between the relayterminal device and the access network equipment and configurationinformation of a D2D communication interface between the relay terminaldevice and the remote terminal device. The configuration information ofthe cellular communication interface is specifically first configurationinformation of a physical layer, and the configuration information ofthe D2D communication interface is specifically second configurationinformation of the physical layer; or, the configuration information ofthe cellular communication interface is specifically first configurationinformation of a physical layer and first configuration information of aLayer 2, and the configuration information of the D2D communicationinterface is specifically at least one of second configurationinformation of the physical layer and second configuration informationof the Layer 2.

In view of the above possible implementations, in a second possibleimplementation of the third aspect, the first configuration informationof the physical layer includes at least one of: information of a firsttransmission resource for relay transmission on the cellularcommunication interface, a relay-specific RNTI, a correspondence betweena data volume interval for relay transmission and a PUCCH resource, or acorrespondence between the data volume interval for relay transmissionand a preamble, wherein the relay-specific RNTI is used by the accessnetwork equipment to scramble a PDCCH for scheduling downlink datatransmission of the remote terminal device; and the second configurationinformation of the physical layer includes: information of a secondtransmission resource for relay transmission on the D2D communicationinterface.

In view of the above possible implementations, in a third possibleimplementation of the third aspect, the first configuration informationof the Layer 2 includes at least one of: a relay-specific LCID or aLayer-2 identifier allocated to the remote terminal device, therelay-specific LCID being used for identifying relay transmission;and/or the second configuration information of the Layer 2 includes: theLayer-2 identifier allocated to the remote terminal device.

In view of the above possible implementations, in a fourth possibleimplementation of the third aspect, the configuration information of theEPS bearer further includes configuration information of a user-planepeer layer between the access network equipment and the remote terminaldevice.

In view of the above possible implementations, in a fifth possibleimplementation of the third aspect, the receiving, by an access networkequipment, a bearer setup request includes: receiving, by the accessnetwork equipment, an RRC message sent by the relay terminal device, theRRC message carrying the bearer setup request; and the setting up, bythe access network equipment, an EPS bearer for the remote terminaldevice according to the bearer setup request includes: transmitting, bythe access network equipment to the core network equipment according tothe RRC message, application layer protocol signaling for requesting thesetup of a bearer for the remote terminal device.

In view of the above possible implementations, in a sixth possibleimplementation of the third aspect, the receiving, by an access networkequipment, a bearer setup request includes: receiving, by the accessnetwork equipment, application layer protocol signaling sent by the corenetwork equipment, the application layer protocol signaling carrying thebearer setup request.

In view of the above possible implementations, in a seventh possibleimplementation of the third aspect, the bearer setup request is furtherconfigured to request the setup of a PDN connection for the remoteterminal device. The method may further include: setting up, by theaccess network equipment, a PDN connection for the remote terminaldevice according to the bearer setup request; and transmitting, by theaccess network equipment, configuration information of the PDNconnection to the relay terminal device.

In a fourth aspect, an apparatus for relay transmission is provided toperform the method in the first aspect or in any possible implementationof the first aspect. Specifically, the apparatus includes units forperforming the method in the first aspect or in any possibleimplementation of the first aspect.

In a fifth aspect, another apparatus for relay transmission is providedto perform the method in the second aspect or in any possibleimplementation of the second aspect. Specifically, the apparatusincludes units for performing the method in the second aspect or in anypossible implementation of the second aspect.

In a sixth aspect, another apparatus for relay transmission is providedto perform the method in the third aspect or in any possibleimplementation of the third aspect. Specifically, the apparatus includesunits for performing the method in the third aspect or in any possibleimplementation of the third aspect.

In a seventh aspect, another apparatus for relay transmission isprovided, which includes: a storage unit and a processor. The storageunit is configured to store instructions. The processor is configured toexecute the instructions stored in the storage unit. When executing theinstructions stored in the storage device, the processor is enabled toperform the method in the first aspect or in any possible implementationof the first aspect.

In an eighth aspect, another apparatus for relay transmission isprovided, which includes: a storage unit and a processor. The storageunit is configured to store instructions. The processor is configured toexecute the instructions stored in the storage unit. When executing theinstructions stored in the storage device, the processor is enabled toperform the method in the second aspect or in any possibleimplementation of the second aspect.

In a ninth aspect, another apparatus for relay transmission is provided,which includes: a storage unit and a processor. The storage unit isconfigured to store instructions. The processor is configured to executethe instructions stored in the storage unit. When executing theinstructions stored in the storage device, the processor is enabled toperform the method in the third aspect or in any possible implementationof the third aspect.

In a tenth aspect, a computer readable medium is provided, which isconfigured to store a computer program. The computer program includesinstructions for performing the method in the first aspect or in anypossible implementation of the first aspect.

In an eleventh aspect, another computer readable medium is provided,which is configured to store a computer program. The computer programincludes instructions for performing the method in the second aspect orin any possible implementation of the second aspect.

In a twelfth aspect, another computer readable medium is provided, whichis configured to store a computer program. The computer program includesinstructions for performing the method in the third aspect or in anypossible implementation of the third aspect.

According to the methods for relay transmission provided by theembodiments of the disclosure, the relay terminal device transmits abearer setup request through the access network equipment, the bearersetup request being configured to request the setup of an EPS bearer forthe remote terminal device; and the access network equipment can set upan EPS bearer for the remote terminal device according to the bearersetup request. The EPS bearer may include a data transmission tunnelbetween the core network equipment and the access network equipment anda radio bearer between the access network equipment and the relayterminal device. Therefore, the relay terminal device can adopt the EPSbearer to relay data transmitted between the remote terminal device andthe core network equipment, such that the relay terminal device does notneed to perform NET traversal, thus reducing the data processingcomplexity of relay transmission.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in the embodiments of the disclosuremore clearly, the following briefly introduces the accompanying drawingsrequired for describing the embodiments or the prior art. Apparently,the accompanying drawings in the following description show merely someembodiments of the disclosure, and persons of ordinary skill in the artmay still derive other drawings from these accompanying drawings withoutcreative efforts.

FIG. 1 is a schematic flow chart of a wireless communication systemapplied in an embodiment of the disclosure.

FIG. 2 is a schematic flow chart of a method for relay transmissionprovided by an embodiment of the disclosure.

FIG. 3 is a schematic diagram illustrating an example of a user-planeprotocol stack for relay communication in each device according to anembodiment of the disclosure.

FIG. 4 is a schematic diagram illustrating an example of anotheruser-plane protocol stack for relay communication in each deviceaccording to an embodiment of the disclosure.

FIG. 5 is a schematic flow chart of another method for relaytransmission provided by an embodiment of the disclosure.

FIG. 6 is a schematic flow chart of another method for relaytransmission provided by an embodiment of the disclosure.

FIG. 7 is a schematic block diagram of a relay terminal device providedby an embodiment of the disclosure.

FIG. 8 is a schematic block diagram of an apparatus for relaytransmission provided by an embodiment of the disclosure.

FIG. 9 is a schematic block diagram of another apparatus for relaytransmission provided by an embodiment of the disclosure.

FIG. 10 is a schematic block diagram of another relay terminal deviceprovided by an embodiment of the disclosure.

FIG. 11 is a schematic block diagram of another apparatus for relaytransmission provided by an embodiment of the disclosure.

FIG. 12 is a schematic block diagram of another apparatus for relaytransmission provided by an embodiment of the disclosure.

DETAILED DESCRIPTION

The following clearly and completely describes the technical solutionsin the embodiments of the disclosure with reference to the accompanyingdrawings in the embodiments of the disclosure. Apparently, the describedembodiments are merely a part rather than all of the embodiments of thedisclosure. All other embodiments obtained by a person of ordinary skillin the art based on the embodiments of the disclosure without creativeefforts shall fall within the protection scope of the disclosure.

It should be understood that, the terms “system” and “network” in thetext can be exchanged. The term “and/or” in the text merely describesassociations between associated objects, and it indicates three types ofrelationships. For example, A and/or B may indicate that A exists alone,A and B coexist, or B exists alone. In addition, the character “/” inthe text generally indicates that the associated objects are in an “or”relationship.

FIG. 1 is a schematic diagram of a wireless communication system 100applied in an embodiment of the disclosure. The wireless communicationsystem 100 may include at least one access network equipment 110. Theaccess network equipment 100 may be a device communicating with terminaldevices. Each of access network equipment 100 may provide communicationcoverage for a specific geographical area, and may communicate withterminal devices within the coverage. The access network equipment 100may be a Base Transceiver Station (BTS) in a GSM system or a CodeDivision Multiple Access (CDMA) system, or a NodeB (NB) in a WCDMAsystem, or an Evolutional Node B (eNB or eNodeB) in an LTE system, or aradio controller in a Cloud Radio Access Network (CRAN). Alternatively,the access network equipment may be a relay station, an access point, avehicle-mounted device, a wearable device, a core network equipment in afuture 5G network, an access network equipment in a future evolvedPublic Land Mobile Network (PLMN), or the like.

The wireless communication system 100 further includes multiple terminaldevices 120 within the coverage of the access network equipment 110. Theterminal devices 120 may be mobile or fixed. Each of terminal devices120 may be an access terminal, a User Equipment (UE), a subscriber unit,a subscriber station, a mobile station, a mobile platform, a remotestation, a remote terminal, a mobile device, a user terminal, aterminal, a wireless communication device, a user agent, or a userdevice. The access terminal may be a cellular phone, a cordless phone, aSession Initiation Protocol (SIP) phone, a Wireless Local Loop (WLL)station, a Personal Digital Assistant (PDA), a handheld device having awireless communication function, a computing device or any otherprocessing device connected to a wireless modem, a vehicle-mounteddevice, a wearable device, a terminal device in a future 5G network, aterminal device in a future evolved PLMN, or the like.

FIG. 1 exemplifies an access network equipment and six terminal devices.Optionally, the wireless communication system 100 may include multipleaccess network equipments, and each access network equipment may coverother quantities of terminal devices. The embodiment of the disclosureis not limited to this. Moreover, the wireless communication system 100may also include an MME, a Serving Gateway (S-GW), a Packet Data NetworkGateway (P-GW), and other network entities. The embodiment of thedisclosure is not limited to this.

Specifically, the terminal devices 120 may communicate in a cellularcommunication mode or D2D communication mode, where in the cellularcommunication mode, a terminal device may communicate with otherterminal devices through the access network equipment; and in the D2Dcommunication mode, a terminal device may directly communicate withother terminal devices through a D2D link.

The multiple terminal devices 120 shown in FIG. 1 include cellularterminal devices, D2D terminal devices, and relay terminal devices. Thecellular terminal device communicates with the access network equipment110 by using a cellular communication technology. The D2D terminaldevice transmits data with the access network equipment through therelay terminal device. The relay terminal device and the D2D terminaldevice are connected via a PC5 interface and communicate by using a D2Dcommunication technology. The D2D communication technology may bespecifically a SideLink (SL) technology in LTE, or a WIFI, Bluetooth orany other technology in WLAN, or any other D2D communication technology.The embodiment of the disclosure is not limited to this. The relayterminal device and the access network equipment are connected via a Uuinterface and communicate by using a cellular communication technology.

FIG. 2 exemplifies a method for relay transmission 200 provided by anembodiment of the disclosure. The method 200 may be applied to thewireless communication system shown in FIG. 1. The embodiment of thedisclosure is not limited to this.

At S210, a relay terminal device transmits a bearer setup request to acore network equipment, the bearer setup request being configured torequest the setup of an EPS bearer for a remote terminal device.

The bearer setup request is configured to request the setup of an EPSbearer for the remote terminal device. For example, the setup of adefault EPS bearer for the remote terminal device or the setup of adedicated EPS bearer for the remote terminal device is requested. Theembodiment of the disclosure is not limited to this.

Optionally, if a PDN connection has not been set up for the remoteterminal device, the bearer setup request can be further configured torequest the setup of a PDN connection for the remote terminal device.The embodiment of the disclosure is not limited to this.

Optionally, the bearer setup request may carry information of the remoteterminal device, for example, a terminal device identifier of the remoteterminal device. Optionally, if a PDN connection has been set up for theremote terminal device, the information of the remote terminal devicemay include an IP address of the remote terminal device. The embodimentof the disclosure is not limited to this.

Optionally, the relay terminal device may transmit the bearer setuprequest after setting up a D2D communication link (also referred to as aPC5 connection) with the remote terminal device. Optionally, the relayterminal device may also transmit the bearer setup request according toa connection setup request after receiving the connection setup requestfrom the remote terminal device, where the connection setup request isconfigured to request the setup of a D2D communication link between therelay terminal device and the remote terminal device. For example, theconnection setup request may be specifically a direct communicationrequest, for requesting the setup of a PC5 link between the relayterminal device and the remote terminal device. The embodiment of thedisclosure is not limited to this.

Optionally, the core network equipment may be specifically an MME orother devices. For ease of description, an MME is taken as an example ofthe core network equipment for illustration below. The embodiment of thedisclosure is not limited to this.

Optionally, the relay terminal device may transmit the bearer setuprequest to the core network equipment by transmitting an RRC message tothe access network equipment. Specifically, the relay terminal devicemay transmit an RRC message to the access network equipment, the RRCmessage carrying the bearer setup request. After receiving the RRCmessage, the access network equipment may transmit, for example,application layer protocol signaling to the core network equipment, torequest the core network equipment to set up an EPS bearer for theremote terminal device. The embodiment of the disclosure is not limitedto this.

Optionally, the relay terminal device may also transmit a NAS message tothe core network equipment, the NAS message carrying the bearer setuprequest. The embodiment of the disclosure is not limited to this.

At S220, after receiving the bearer setup request, the core networkequipment may set up an EPS bearer for the remote terminal devicetogether with the access network equipment according to the bearer setuprequest, where the EPS bearer includes a cellular data transmissionchannel between the access network equipment and the relay terminaldevice and a D2D data transmission channel between the relay terminaldevice and the remote terminal device.

Optionally, the EPS bearer may also include a data transmission channelbetween the core network equipment and the access network equipment anda data transmission channel between the core network equipment and aP-GW. Optionally, the data transmission channel between the core networkequipment and the access network equipment and the data transmissionchannel between the core network equipment and the P-GW may becollectively referred to as GPRS Tunnelling Protocol (GTP) tunnels. Theembodiment of the disclosure is not limited to this.

Optionally, if the EPS bearer is a default bearer for the remoteterminal device, the core network equipment may further authenticate theremote terminal device, for example, perform identity authentication orsecurity authentication, before setting up the EPS bearer. Theembodiment of the disclosure is not limited to this.

Optionally, the core network equipment may transmit the information ofthe remote terminal device to the P-GW, such that the P-GW sets up a GTPtunnel for the remote terminal device according to the information ofthe remote terminal device. Optionally, the core network equipment mayalso receive configuration information of the GTP tunnel sent by theP-GW, for example, a Tunnel Endpoint Identifier (TEID) allocated to theremote terminal device. The embodiment of the disclosure is not limitedto this.

Optionally, the core network equipment may also transmit applicationlayer protocol signaling to the access network equipment, where theapplication layer protocol signaling may carry the terminal deviceidentifier of the remote terminal device, such that the access networkequipment sets up a radio bearer for the remote terminal deviceaccording to the application layer protocol signaling. The radio bearerfor the remote terminal device may include the data transmission channelbetween the access network equipment and the relay terminal device andthe data transmission channel between the relay terminal device and theremote terminal device. Optionally, the application layer protocolsignaling may be specifically an initial context setup request, a RadioAccess Bearer (RAB) setup request, or the like. The embodiment of thedisclosure is not limited to this.

At S230, the access network equipment transmits a reconfigurationmessage to the relay terminal device, the reconfiguration messagecarrying configuration information of the EPS bearer set up for theremote terminal device.

Optionally, the reconfiguration message may be specifically an RRCconnection reconfiguration message, and the configuration information ofthe EPS bearer may include configuration information of a radio bearerset up by the access network equipment for the remote terminal device.For example, the configuration information of the radio bearer mayinclude at least one of : configuration information of a user-plane peerlayer between the access network equipment and the relay terminaldevice, configuration information of a user-plane peer layer between therelay terminal device and the remote terminal device, or configurationinformation of a user-plane peer layer between the access networkequipment and the remote terminal device. The embodiment of thedisclosure is not limited to this.

Optionally, in the embodiment of the disclosure, the relay terminaldevice may relay data transmitted between the remote terminal device andthe network equipment through a layer other than the IP layer. Forexample, the relay terminal device may adopt a Layer-1 relay or Layer-2relay manner. The Layer-1 relay may be specifically a physical layerrelay, and the Layer-2 relay may be specifically a Media Access Control(MAC) layer relay, a Radio Link Control (RLC) layer relay, or a PacketData Convergence Protocol (PDCP) layer relay. The relay transmissionmanner adopted by the relay terminal device is not limited in theembodiment of the disclosure.

Optionally, the relay terminal device may adopt the Layer-1 relaymanner. In this case, a user-plane protocol stack of the relay terminaldevice may only include a physical layer. In an example of theuser-plane protocol stack shown in FIG. 3, the physical layer of therelay terminal device is a peer layer of a physical layer of the remoteterminal device and is a peer layer of a physical layer of the networkequipment, and higher layers (for example, Layer 2 and Layer 3) of thenetwork equipment and the remote terminal device are peer layers. Theembodiment of the disclosure is not limited to this. In this case,optionally, when data are required to be transmitted to each other, thenetwork equipment or the remote terminal device may encapsulate the datainto a MAC PDU carrying identification information of the remoteterminal device, process the MAC PDU through the physical layer togenerate a physical layer data frame, and transmit the physical layerdata frame to the relay terminal device through the physical layer.After receiving the physical layer data frame sent by the remoteterminal device or the network equipment, the relay terminal device mayprocess and forward the data carried in the received physical layer dataframe at the physical layer, and does not identify the remote terminaldevice corresponding to the physical layer data frame. Correspondingly,the network equipment or the remote terminal device that receives thedata sent by the relay terminal device through the physical layer mayidentify the remote terminal device corresponding to the data at ahigher layer (for example, Layer 2 or Layer 3). The embodiment of thedisclosure is not limited to this.

In this case, optionally, the configuration information of the radiobearer may include the configuration information of the user-plane peerlayer between the access network equipment and the relay terminaldevice, that is, configuration information of a cellular communicationinterface between the relay terminal device and the access networkequipment. The configuration information of the cellular communicationinterface may include configuration information of a Layer 1 (that is,physical layer) used by the access network equipment and the relayterminal device to perform relay transmission with each other. For easeof description, the configuration information may be referred to asfirst configuration information of the physical layer. The embodiment ofthe disclosure is not limited to this. Optionally, the firstconfiguration information of the physical layer includes at least oneof: information of a first transmission resource for relay transmission,a relay-specific RNTI, a correspondence between a data volume intervalfor relay transmission and a PUCCH resource, or a correspondence betweenthe data volume interval for relay transmission and a preamble.Alternatively, the first configuration information of the physical layermay further include other information for relay transmission. Theembodiment of the disclosure is not limited to this.

Specifically, the first transmission resource for relay transmission maybe specifically used for transmitting relay data between the relayterminal device and the access network equipment. Therefore, when therelay terminal device receives a physical layer data frame transmittedby the access network equipment using the first transmission resource,or, when the access network equipment receives a physical layer dataframe transmitted by the relay terminal device using the firsttransmission resource, it can be determined, according to the firsttransmission resource occupied by the physical layer data frame, thatthe physical layer data frame carries relay data. The embodiment of thedisclosure is not limited to this.

The relay-specific RNTI can be used for identifying the relay data.Specifically, the access network equipment may scramble, by using therelay-specific RNTI, a PDCCH for scheduling downlink data transmissionof the remote terminal device, such that the relay terminal device candetermine, through addressing by using the relay-specific RNTI, that thereceived physical layer data frame carries relay data. The embodiment ofthe disclosure is not limited to this.

When the relay terminal device needs to relay data of the remoteterminal device to the network equipment, optionally, the relay terminaldevice may request an uplink grant from the network equipment. As anoptional embodiment, the relay terminal device may transmit a bufferstatus report to the network equipment, the buffer status reportcarrying information of the data buffer size of the relay terminaldevice, such that the network equipment can allocate an uplinktransmission resource to the relay terminal device according to thebuffer status report.

As another optional embodiment, the first configuration information ofthe physical layer may also include a correspondence between a datavolume interval for relay transmission and a PUCCH resource. Therefore,the relay terminal device may determine, according to the correspondencebetween the data volume interval and the PUCCH resource, a PUCCHresource corresponding to a data volume to be relayed, and adopt thecorresponding PUCCH resource to transmit a scheduling request to thenetwork equipment. In this case, the network equipment may determine,according to the PUCCH resource occupied by the scheduling request, ato-be-transmitted data volume interval of the relay terminal device, andallocate an uplink transmission resource accordingly. The embodiment ofthe disclosure is not limited to this.

As another optional embodiment, the first configuration information ofthe physical layer may also include a correspondence between a datavolume interval for relay transmission and a preamble. In this case, therelay terminal device may request an uplink grant by transmitting apreamble to the network equipment. Specifically, the relay terminaldevice may determine, according to the correspondence between the datavolume interval and the preamble, a preamble corresponding to a datavolume to be relayed, and transmit the corresponding preamble to thenetwork equipment. In this case, the network equipment may determine,according to the corresponding preamble, a to-be-transmitted data volumeinterval of the relay terminal device, and allocate an uplinktransmission resource accordingly. The embodiment of the disclosure isnot limited to this.

Optionally, the first configuration information of the physical layermay further include the configuration information of the user-plane peerlayer between the relay terminal device and the remote terminal device,that is, configuration information of a D2D communication interfacebetween the relay terminal device and the remote terminal device. Theconfiguration information of the D2D communication interface may includeconfiguration information of a Layer 1 (that is, physical layer) used bythe relay terminal device and the remote terminal device to performrelay transmission with each other. For ease of description, theconfiguration information may be referred to as second configurationinformation of the physical layer. The embodiment of the disclosure isnot limited to this. Optionally, the second configuration information ofthe physical layer may include information of a second transmissionresource for relay transmission, where the second transmission resourceis used for relay transmission between the relay terminal device and theremote terminal device. Therefore, when the relay terminal devicereceives a physical layer data frame transmitted by the remote terminaldevice using the second transmission resource, or when the remoteterminal device receives a physical layer data frame transmitted by therelay terminal device using the second transmission resource, it can bedetermined, according to the second transmission resource occupied bythe physical layer data frame, that the physical layer data framecarries relay data. The embodiment of the disclosure is not limited tothis.

Optionally, the second configuration information of the physical layermay also include other information. The embodiment of the disclosure isnot limited to this.

Optionally, the configuration information of the radio bearer mayfurther include the configuration information of the user-plane peerlayer between the access network equipment and the remote terminaldevice. For example, the configuration information of the radio bearerfurther includes at least one of configuration information of a MAClayer, configuration information of an RLC layer, or configurationinformation of a PDCP layer. In this case, the relay terminal device mayalso transmit, to the remote terminal device, the configurationinformation of the user-plane peer layer between the access networkequipment and the remote terminal device. After receiving theconfiguration information, the remote terminal device may configure atleast one of a MAC layer, an RLC layer, or a PDCP layer. The embodimentof the disclosure is not limited to this.

Optionally, the relay terminal device may also adopt a Layer-2 relaymanner, for example, a MAC layer relay, an RLC layer relay, or a PDCPlayer relay manner. In this case, a user-plane protocol stack of therelay terminal device may only include at least one of a physical layerand a Layer 2. In an example of the user-plane protocol stack shown inFIG. 4, the relay terminal device adopts a MAC layer relay manner. Inthis case, the physical layer of the relay terminal device is a peerlayer of a physical layer of the remote terminal device and is a peerlayer of a physical layer of the network equipment, a MAC layer of therelay terminal device is a peer layer of a MAC layer of the networkequipment and is a peer layer of a MAC layer of the remote terminaldevice, and RLC layers, PDCP layers, and higher layers of the networkequipment and the remote terminal device are peer layers. The embodimentof the disclosure is not limited to this. In this case, optionally, therelay terminal device may identify the remote terminal device accordingto identification information of the remote terminal device, where theidentification information of the remote terminal device may include aterminal device identifier of the remote terminal device or a Layer-2identifier. Optionally, when needing to transmit data to each other, thenetwork equipment or the remote terminal device may encapsulate the datainto a Layer-2 PDU, that is, a PDU generated after Layer-2 and Layer-1encapsulation, where the Layer-2 PDU may carry the identificationinformation of the remote terminal device. Alternatively, when theaccess network equipment transmits relay data to the relay terminaldevice, the network equipment may schedule the Layer-2 PDU through aPDCCH scrambled by using an RNTI of the remote terminal device. Whenreceiving the Layer-2 PDU sent by the remote terminal device or thenetwork equipment, the relay terminal device may process the receivedLayer-2 PDU on the Layer 2. For example, the relay terminal deviceidentifies the remote terminal device corresponding to the receivedLayer-2 PDU according to the identification information of the remoteterminal device at the Layer 2; or encapsulates, according to theidentification information of the remote terminal device, the Layer-2PDU sent to a receiving end device at the Layer 2. The embodiment of thedisclosure is not limited to this.

In this case, optionally, the configuration information of theuser-plane peer layer between the access network equipment and the relayterminal device may specifically include configuration information of aLayer 1 and a Layer 2 used by the access network equipment and the relayterminal device to perform relay transmission with each other.Corresponding to the user-plane protocol stack, the configurationinformation of the Layer 2 may include configuration information of aMAC layer, or further include configuration information of an RLC layer,or further include configuration information of an RLC layer and a PDCPlayer. For ease of understanding, the configuration information of theLayer 1 and the Layer 2 may be referred to as first configurationinformation of the physical layer and first configuration information ofthe Layer 2 respectively. The embodiment of the disclosure is notlimited to this.

Optionally, reference can be made to the above description for the firstconfiguration information of the physical layer, and the details are notrepeatedly described herein for brevity. As another optional embodiment,the first configuration information of the physical layer may furtherinclude a target preamble allocated by the network equipment to theremote terminal device. In this case, when the relay terminal deviceneeds to relay data of the remote terminal device to the access networkequipment, the relay terminal device may initiate an uplink grantrequest to the access network equipment by using the target preamble;and the access network equipment may determine the remote terminaldevice corresponding to the uplink grant request according to the targetpreamble, and allocate an uplink transmission resource to the data ofthe remote terminal device. The embodiment of the disclosure is notlimited to this.

As another optional embodiment, the first configuration information ofthe physical layer may also include an RNTI allocated by the networkequipment to the remote terminal device. In this case, when the accessnetwork equipment needs to transmit data of the remote terminal device,the access network equipment may scramble, by using the RNTI allocatedto the remote terminal device, a PDCCH for scheduling downlink datatransmission of the remote terminal device, such that the relay terminaldevice can determine the remote terminal device corresponding to thereceived Layer-2 PDU through addressing by using the RNTI. Theembodiment of the disclosure is not limited to this.

Optionally, the first configuration information of the Layer 2 mayinclude at least one of: a relay-specific LCID, a Layer-2 identifierallocated to the remote terminal device, or an RNTI allocated to theremote terminal device. Alternatively, the first configurationinformation of the Layer 2 may also include other information for relaytransmission. The embodiment of the disclosure is not limited to this.

Specifically, the relay-specific LCID can be used for identifying relaytransmission. In this case, when the access network equipment receivesthe Layer-2 PDU sent by the relay terminal device or the relay terminaldevice receives the Layer-2 PDU sent by the access network equipment, itcan be determined, according to the relay-specific LCID carried in theLayer-2 PDU, that the Layer-2 PDU carries relay data. The embodiment ofthe disclosure is not limited to this.

The Layer-2 identifier may be an identifier encapsulated and identifiedat the Layer 2, and the Layer-2 identifier can be used for identifyingthe remote terminal device in relay transmission. Optionally, the lengthof the Layer-2 identifier may be less than the length of the terminaldevice, and therefore, the signaling overhead can be reduced by carryingthe Layer-2 identifier in the PDU as compared with the situation thatthe terminal device identifier is carried in the Layer-2 PDU. Theembodiment of the disclosure is not limited to this. Optionally, theLayer-2 identifier may be set at a MAC layer, an RLC layer, or a PDCPlayer. Alternatively, the Layer 2 of the remote terminal device and theaccess network equipment may be further added with an adaptation layer,where the adaptation layer may be placed at any position between the MAClayer and the PDCP layer, and the Layer-2 identifier may be set at theadaptation layer. The embodiment of the disclosure is not limited tothis.

Optionally, the configuration information of the user-plane peer layerbetween the relay terminal device and the remote terminal device mayinclude configuration information of the physical layer and the Layer 2used by the relay terminal device and the remote terminal device toperform relay transmission with each other. For ease of description, theconfiguration information of the physical layer and the Layer 2 may bereferred to as second configuration information of the physical layerand second configuration information of the Layer 2 respectively. Theembodiment of the disclosure is not limited to this. Specifically,reference can be made to the above description for the secondconfiguration information of the physical layer, and the details are notrepeatedly described herein for brevity. The second configurationinformation of the Layer 2 may include the Layer-2 identifier of theremote terminal device or other information. The embodiment of thedisclosure is not limited to this.

Optionally, the configuration information of the user-plane peer layerbetween the access network equipment and the remote terminal device mayinclude at least one of configuration information of an RLC layer andconfiguration information of a PDCP layer. In this case, the relayterminal device may transmit, to the remote terminal device, indicationinformation that indicates at least one of the configuration informationof the RLC layer and the configuration information of the PDCP layer,such that the remote terminal device performs correspondingconfigurations. The embodiment of the disclosure is not limited to this.

Optionally, if the bearer setup request is further configured to requestthe setup of a PDN connection for the remote terminal device, the accessnetwork equipment and the core network equipment may set up a PDNconnection for the remote terminal device, and transmit configurationinformation of the PDN connection, for example, an IP address, to therelay terminal device. In this case, optionally, the relay terminaldevice may also transmit the configuration information of the PDNconnection to the remote terminal device. The embodiment of thedisclosure is not limited to this.

Optionally, the relay terminal device may perform correspondingconfigurations according to the configuration information of the EPSbearer, and after completion of the configurations, transmit areconfiguration complete message (for example, an RRC connectionreconfiguration complete message) and an uplink information transfermessage to the access network equipment. The embodiment of thedisclosure is not limited to this.

In view of the above, according to the method for relay transmissionprovided by the embodiment of the disclosure, the relay terminal devicetransmits a bearer setup request to the core network equipment, thebearer setup request being configured to request the setup of an EPSbearer for the remote terminal device; and the core network equipmentand the access network equipment set up an EPS bearer for the remoteterminal device according to the bearer setup request, where the EPSbearer includes a cellular data transmission channel between the accessnetwork equipment and the relay terminal device and a D2D datatransmission channel between the relay terminal device and the remoteterminal device. Therefore, the relay terminal device can adopt the EPSbearer to relay data transmitted between the remote terminal device andthe access network equipment, such that the relay terminal device canrelay in different manners and does not need to perform NET traversal,thus reducing the data processing complexity of relay transmission.

The embodiments of the disclosure will be described in detail below withreference to specific examples. It should be noted that, these examplesare merely provided for persons skilled in the art to better understandthe embodiments of the disclosure, and are not intended to limit thescope of the embodiments of the disclosure.

For ease of description, it is assumed in the following examples that aPDN connection and a bearer have been set up for the remote terminaldevice in a cellular network, the remote terminal device is specificallya remote UE, the relay terminal device is specifically a relay UE, and anetwork equipment is specifically an eNB. The embodiment of thedisclosure is not limited to this.

FIG. 5 exemplifies a bearer setup method 300 provided by an embodimentof the disclosure. In the method 300, it is assumed that the remoteterminal device has attached to a cellular network (for example, anEvolved Universal Terrestrial Radio Access Network (E-UTRAN)), or theremote terminal device has set up a PDN connection with the cellularnetwork. The embodiment of the disclosure is not limited to this.

At S310, the remote terminal device discovers the relay terminal deviceand resides in the relay terminal device.

At S320, the remote terminal device transmits a direct communicationrequest to the relay terminal device, where the direct communicationrequest may carry a terminal device identifier of the remote terminaldevice and an IP address of a PDN connection for the remote terminaldevice.

The direct communication request may be specifically used for setting upa D2D communication link between the remote terminal device and therelay terminal device, for example, a PC5 connection between the remoteterminal device and the relay terminal device. The embodiment of thedisclosure is not limited to this.

At S330, after receiving the direct communication request sent by theremote terminal device, the relay terminal device reports, through theeNB, the terminal device identifier of the remote terminal device andthe IP address of the PDN connection to the MME.

At S340, the MME may store the terminal device identifier and the IPaddress, and transmit the terminal device identifier and the IP addressto the P-GW (or S-GW).

At S350, the MME and the P-GW allocate, to the remote terminal device, aGTP tunnel of an S1-U interface, for example, a TEID.

At S360, the eNB allocates a radio bearer between the relay terminaldevice and the eNB to the remote terminal device.

Optionally, the configuration information of the radio bearer mayinclude configuration information of a physical layer or includeconfiguration information of a physical layer and configurationinformation of a MAC layer. Optionally, the configuration information ofthe MAC layer may include a Layer-2 identifier allocated to the remoteterminal device. Alternatively, the eNB may also transmit configurationof an RLC layer and/or configuration of a PDCP layer of the remoteterminal device to the relay terminal device. The embodiment of thedisclosure is not limited to this.

At S330, the relay terminal device transmits a direct communicationresponse to the remote terminal device.

Optionally, the direct communication response may carry the Layer-2identifier and/or an RRC container, where the RRC container mayencapsulate the configuration of the RLC layer and/or the configurationof the PDCP layer. Correspondingly, after receiving the directcommunication response, the remote terminal device may configure acorresponding RLC layer and/or PDCP layer according to the RRC containerin the direct communication response. The embodiment of the disclosureis not limited to this.

FIG. 6 exemplifies another bearer setup method 400 provided by anembodiment of the disclosure. In the method 400, it is assumed that theremote terminal device has not set up a PDN connection.

At S410, the remote terminal device discovers the relay terminal deviceand resides in the relay terminal device.

At S420, the remote terminal device transmits a direct communicationrequest to the relay terminal device, where the direct communicationrequest may carry a terminal device identifier of the remote terminaldevice and indication information for requesting the setup of a PDNconnection.

In this case, the direct communication request may be configured torequest the setup of a PC5 connection between the remote terminal deviceand the relay terminal device, and may also be configured to request thesetup of a PDN connection between the remote terminal device and acellular network.

At S430, the relay terminal device may transmit a PDN connection setuprequest to the MME through the eNB according to the direct communicationrequest, to request the setup of a PDN connection for the remoteterminal device. Optionally, the PDN connection setup request may carrythe terminal device identifier of the remote terminal device.

At S440, the core network equipment (MME or S-GW/P-GW) creates a PDNconnection for the remote terminal device and allocates an IP address tothe remote terminal device.

At S450, the MME transmits a PDN connection setup response to the relayterminal device through the eNB, the PDN connection setup responsecarrying configuration information of the PDN connection, for example,an IP address.

At S460, the MME allocates, to the remote terminal device, a GTP tunnelof an S1-U, for example, a TEID.

At S430, the eNB allocates a radio bearer between the relay terminaldevice and the eNB to the remote terminal device.

Optionally, the configuration information of the radio bearer mayinclude configuration information of a physical layer or includeconfiguration information of a physical layer and configurationinformation of a Layer 2. The embodiment of the disclosure is notlimited to this.

At S440, the relay terminal device transmits a direct communicationresponse to the remote terminal device.

Optionally, the direct communication response may carry a Layer-2identifier and/or an RRC container, and may also carry information ofthe PDN connection, for example, an IP address. The embodiment of thedisclosure is not limited to this.

It should be noted that, the examples in FIG. 3 to FIG. 6 are providedfor persons skilled in the art to better understand the embodiments ofthe disclosure, and are not intended to limit the scope of theembodiments of the disclosure. It is apparent to persons skilled in theart that equivalent modifications or changes can be made according tothe examples in FIG. 3 to FIG. 6, and these modifications or changesalso fall within the scope of the embodiments of the disclosure.

It should be understood that, the serial number of each process does notindicate the order of performing the process. The order of performingeach process should be determined by its function and internal logic,and shall not limit the implementation of the embodiments of thedisclosure.

The method for relay transmission according to the embodiments of thedisclosure is described in detail above with reference to FIG. 1 to FIG.6, and an apparatus for relay transmission according to embodiments ofthe disclosure will be described in detail below with reference to FIG.7 to FIG. 12.

FIG. 7 shows a relay terminal device 500 provided by an embodiment ofthe disclosure. As shown in FIG. 7, the relay terminal device 500includes:

a transmission unit 510, configured to transmit a bearer setup requestto a core network equipment, the bearer setup request being configuredto request the setup of an EPS bearer for a remote terminal device; and

a receiving unit 520, configured to receive a reconfiguration messagesent by an access network equipment, the reconfiguration messagecarrying configuration information of the EPS bearer set up for theremote terminal device, where the EPS bearer includes a cellular datatransmission channel between the access network equipment and the relayterminal device and a D2D data transmission channel between the relayterminal device and the remote terminal device.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

Optionally, the configuration information of the EPS bearer includesconfiguration information of a cellular communication interface betweenthe relay terminal device and the access network equipment andconfiguration information of a D2D communication interface between therelay terminal device and the remote terminal device.

Optionally, the configuration information of the cellular communicationinterface is specifically first configuration information of a physicallayer, and the configuration information of the D2D communicationinterface is specifically second configuration information of thephysical layer; or

the configuration information of the cellular communication interface isspecifically first configuration information of a physical layer andfirst configuration information of a Layer 2, and the configurationinformation of the D2D communication interface is specifically at leastone of second configuration information of the physical layer and secondconfiguration information of the Layer 2.

Optionally, the first configuration information of the physical layerincludes at least one of: information of a first transmission resourcefor relay transmission on the cellular communication interface, arelay-specific RNTI, a correspondence between a data volume interval forrelay transmission and a PUCCH resource, and a correspondence betweenthe data volume interval for relay transmission and a preamble, wherethe relay-specific RNTI is used by the access network equipment toscramble a PDCCH for scheduling downlink data transmission of the remoteterminal device.

Optionally, the second configuration information of the physical layerincludes: information of a second transmission resource for relaytransmission on the D2D communication interface.

Optionally, the first configuration information of the Layer 2 includesat least one of: a relay-specific LCID and a Layer-2 identifierallocated to the remote terminal device, the relay-specific LCID beingused for identifying relay transmission.

Optionally, the second configuration information of the Layer 2includes: the Layer-2 identifier allocated to the remote terminaldevice.

Optionally, the configuration information of the EPS bearer furtherincludes configuration information of a user-plane peer layer betweenthe access network equipment and the remote terminal device.

Correspondingly, the transmission unit 510 is further configured totransmit, to the remote terminal device, the configuration informationof the user-plane peer layer between the access network equipment andthe remote terminal device.

Optionally, the receiving unit 520 is further configured to receive aconnection setup request from the remote terminal device before thetransmission unit 510 transmits a bearer setup request to the corenetwork equipment, the connection setup request being configured torequest the setup of a D2D communication link between the relay terminaldevice and the remote terminal device.

Correspondingly, the transmission unit 510 is specifically configured totransmit a bearer setup request to the core network equipment accordingto the connection setup request received by the receiving unit 520.

Optionally, the transmission unit 510 is specifically configured totransmit a NAS message to the core network equipment, the NAS messageresponding to the bearer setup request.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device; and correspondingly, the EPSbearer is set up by the core network equipment in a manner oftransmitting application layer protocol signaling to the access networkequipment, the application layer protocol signaling carrying theterminal device identifier of the remote terminal device.

Optionally, the transmission unit 510 is specifically configured totransmit an RRC message to the access network equipment, the RRC messagecarrying the bearer setup request, such that the access networkequipment transmits, to the core network equipment according to the RRCmessage, application layer protocol signaling for requesting the setupof a bearer for the remote terminal device.

Optionally, the bearer setup request is further configured to requestthe setup of a PDN connection for the remote terminal device. In thiscase, the reconfiguration message further carries configurationinformation of the PDN connection set up for the remote terminal device.The transmission unit 510 is further configured to transmit theconfiguration information of the PDN connection to the remote terminaldevice.

In an optional example, the relay terminal device 500 may correspond tothe relay terminal device in the above method embodiments, and may beconfigured to perform each step and/or process corresponding to therelay terminal device in the above method embodiments. The details arenot repeatedly described herein for brevity.

FIG. 8 shows an apparatus for relay transmission 600 provided by anembodiment of the disclosure. As shown in FIG. 8, the apparatus 600includes:

a receiving unit 610, configured to receive a bearer setup request sentby a relay terminal device, the bearer setup request being configured torequest the setup of an EPS bearer for a remote terminal device; and

a processing unit 620, configured to set up an EPS bearer for the remoteterminal device according to the bearer setup request received by thereceiving unit 610, where the EPS bearer includes a cellular datatransmission channel between the access network equipment and the relayterminal device and a D2D data transmission channel between the relayterminal device and the remote terminal device.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

Optionally, the receiving unit 610 is specifically configured to receivea NAS message sent by the relay terminal device, the NAS messageresponding to the bearer setup request.

Correspondingly, the apparatus 600 further includes: a transmissionunit, where the processing unit 620 is specifically configured totransmit application layer protocol signaling to the access networkequipment through the transmission unit, the application layer protocolsignaling carrying the terminal device identifier of the remote terminaldevice.

Optionally, the receiving unit 610 is specifically configured to receiveapplication layer protocol signaling sent by the access networkequipment, where the application layer protocol signaling is sent by theaccess network equipment according to an RRC message sent by the relayterminal device, and the RRC message carries the bearer setup request.

In an optional example, the apparatus 600 may correspond to the corenetwork equipment in the above method embodiments, and may be configuredto perform each step and/or process corresponding to the core networkequipment in the above method embodiments. The details are notrepeatedly described herein for brevity.

FIG. 9 shows another apparatus for relay transmission 700 provided by anembodiment of the disclosure. As shown in FIG. 9, the apparatus 700includes:

a receiving unit 710, configured to receive a bearer setup request forrequesting the setup of an EPS bearer for a remote terminal device;

a processing unit 720, configured to set up an EPS bearer for the remoteterminal device according to the bearer setup request received by thereceiving unit 710, where the EPS bearer includes a cellular datatransmission channel between the access network equipment and a relayterminal device and a D2D data transmission channel between the relayterminal device and the remote terminal device; and

a transmission unit 730, configured to transmit a reconfigurationmessage to the relay terminal device, the reconfiguration messagecarrying configuration information of the EPS bearer set up by theprocessing unit 720.

Optionally, the configuration information of the EPS bearer includesconfiguration information of a cellular communication interface betweenthe relay terminal device and the access network equipment andconfiguration information of a D2D communication interface between therelay terminal device and the remote terminal device.

Optionally, the configuration information of the cellular communicationinterface is specifically first configuration information of a physicallayer, and the configuration information of the D2D communicationinterface is specifically second configuration information of thephysical layer; or

the configuration information of the cellular communication interface isspecifically first configuration information of a physical layer andfirst configuration information of a Layer 2, and the configurationinformation of the D2D communication interface is specifically at leastone of second configuration information of the physical layer and secondconfiguration information of the Layer 2.

Optionally, the first configuration information of the physical layerincludes at least one of: information of a first transmission resourcefor relay transmission on the cellular communication interface, arelay-specific RNTI, a correspondence between a data volume interval forrelay transmission and a PUCCH resource, and a correspondence betweenthe data volume interval for relay transmission and a preamble, wherethe relay-specific RNTI is used by the access network equipment toscramble a PDCCH for scheduling downlink data transmission of the remoteterminal device.

Optionally, the second configuration information of the physical layerincludes: information of a second transmission resource for relaytransmission on the D2D communication interface.

Optionally, the first configuration information of the Layer 2 includesat least one of: a relay-specific LCID and a Layer-2 identifierallocated to the remote terminal device, the relay-specific LCID beingused for identifying relay transmission.

Optionally, the second configuration information of the Layer 2includes: the Layer-2 identifier allocated to the remote terminaldevice.

Optionally, the configuration information of the EPS bearer furtherincludes configuration information of a user-plane peer layer betweenthe access network equipment and the remote terminal device.

Optionally, the receiving unit 710 is specifically configured to receivean RRC message sent by the relay terminal device, the RRC messagecarrying the bearer setup request.

Correspondingly, the processing unit 720 is specifically configured totransmit, through the transmission unit 730 to the core networkequipment according to the RRC message, application layer protocolsignaling for requesting the setup of a bearer for the remote terminaldevice.

Optionally, the receiving unit 710 is specifically configured to receiveapplication layer protocol signaling sent by the core network equipment,the application layer protocol signaling carrying the bearer setuprequest.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

Optionally, the bearer setup request is further configured to requestthe setup of a PDN connection for the remote terminal device. In thiscase, the processing unit 720 is further configured to set up a PDNconnection for the remote terminal device according to the bearer setuprequest. Correspondingly, the transmission unit 730 is furtherconfigured to transmit configuration information of the PDN connectionto the relay terminal device.

In an optional example, the apparatus 700 may correspond to the accessnetwork equipment in the above method embodiments, and may be configuredto perform each step and/or process corresponding to the access networkequipment in the above method embodiments. The details are notrepeatedly described herein for brevity.

It should be understood that, the device 500, the apparatus 600, and theapparatus 700 are embodied in the form of functional units. The term“unit” here may refer to an Application Specific Integrated Circuit(ASIC), an electronic circuit, a processor configured to execute one ormore software or firmware programs (for example, a shared processor,dedicated processor, or group processor), a storage device, a combinedlogic circuit, and/or any other suitable component that supports thedescribed function.

FIG. 10 shows a relay terminal device 800 provided by an embodiment ofthe disclosure. As shown in FIG. 10, the relay terminal device 800includes:

a transmiter 810, configured to transmit a bearer setup request to acore network equipment, the bearer setup request being configured torequest the setup of an EPS bearer for a remote terminal device; and

a receiver 820, configured to receive a reconfiguration message sent byan access network equipment, the reconfiguration message carryingconfiguration information of the EPS bearer set up for the remoteterminal device, where the EPS bearer includes a cellular datatransmission channel between the access network equipment and the relayterminal device and a D2D data transmission channel between the relayterminal device and the remote terminal device.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

Optionally, the configuration information of the EPS bearer includesconfiguration information of a cellular communication interface betweenthe relay terminal device and the access network equipment andconfiguration information of a D2D communication interface between therelay terminal device and the remote terminal device.

Optionally, the configuration information of the cellular communicationinterface is specifically first configuration information of a physicallayer, and the configuration information of the D2D communicationinterface is specifically second configuration information of thephysical layer; or

the configuration information of the cellular communication interface isspecifically first configuration information of a physical layer andfirst configuration information of a Layer 2, and the configurationinformation of the D2D communication interface is specifically at leastone of second configuration information of the physical layer and secondconfiguration information of the Layer 2.

Optionally, the first configuration information of the physical layerincludes at least one of: information of a first transmission resourcefor relay transmission on the cellular communication interface, arelay-specific RNTI, a correspondence between a data volume interval forrelay transmission and a PUCCH resource, and a correspondence betweenthe data volume interval for relay transmission and a preamble, wherethe relay-specific RNTI is used by the access network equipment toscramble a PDCCH for scheduling downlink data transmission of the remoteterminal device.

Optionally, the second configuration information of the physical layerincludes: information of a second transmission resource for relaytransmission on the D2D communication interface.

Optionally, the first configuration information of the Layer 2 includesat least one of: a relay-specific LCID and a Layer-2 identifierallocated to the remote terminal device, the relay-specific LCID beingused for identifying relay transmission.

Optionally, the second configuration information of the Layer 2includes: the Layer-2 identifier allocated to the remote terminaldevice.

Optionally, the configuration information of the EPS bearer furtherincludes configuration information of a user-plane peer layer betweenthe access network equipment and the remote terminal device.

Correspondingly, the transmiter 810 is further configured to transmit,to the remote terminal device, the configuration information of theuser-plane peer layer between the access network equipment and theremote terminal device.

Optionally, the receiver 820 is further configured to receive aconnection setup request from the remote terminal device before thetransmiter 810 transmits a bearer setup request to the core networkequipment, the connection setup request being configured to request thesetup of a D2D communication link between the relay terminal device andthe remote terminal device.

Correspondingly, the transmiter 810 is specifically configured totransmit a bearer setup request to the core network equipment accordingto the connection setup request received by the receiver 820.

Optionally, the transmiter 810 is specifically configured to transmit aNAS message to the core network equipment, the NAS message responding tothe bearer setup request.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device; and correspondingly, the EPSbearer is set up by the core network equipment in a manner oftransmitting application layer protocol signaling to the access networkequipment, the application layer protocol signaling carrying theterminal device identifier of the remote terminal device.

Optionally, the transmiter 810 is specifically configured to transmit anRRC message to the access network equipment, the RRC message carryingthe bearer setup request, such that the access network equipmenttransmits, to the core network equipment according to the RRC message,application layer protocol signaling for requesting the setup of abearer for the remote terminal device.

Optionally, the bearer setup request is further configured to requestthe setup of a PDN connection for the remote terminal device. In thiscase, the reconfiguration message further carries configurationinformation of the PDN connection set up for the remote terminal device.The transmiter 810 is further configured to transmit the configurationinformation of the PDN connection to the remote terminal device.

In an optional example, the relay terminal device 800 may correspond tothe relay terminal device in the above method embodiments, and may beconfigured to perform each step and/or process corresponding to therelay terminal device in the above method embodiments. Optionally, thedevice 800 may further include a storage device and a processor. Thestorage device may include a Read-Only Memory (ROM) and a Random AccessMemory (RAM), and provide instructions and data to the processor. A partof the storage device may further include a non-volatile RAM. Forexample, the storage device may also store information about the devicetype. The processor may be configured to execute the instructions storedin the storage device, and when executing the instructions stored in thestorage device, the processor performs each step and/or process in theabove method embodiments.

FIG. 11 shows an apparatus for relay transmission 900 provided by anembodiment of the disclosure. As shown in FIG. 11, the apparatus 900includes:

a receiver 910, configured to receive a bearer setup request sent by arelay terminal device, the bearer setup request being configured torequest the setup of an EPS bearer for a remote terminal device; and

a processor 920, configured to set up an EPS bearer for the remoteterminal device according to the bearer setup request received by thereceiver 910, where the EPS bearer includes a cellular data transmissionchannel between the access network equipment and the relay terminaldevice and a D2D data transmission channel between the relay terminaldevice and the remote terminal device.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

Optionally, the receiver 910 is specifically configured to receive a NASmessage sent by the relay terminal device, the NAS message responding tothe bearer setup request.

Correspondingly, the apparatus 900 further includes: a transmiter, wherethe processor 920 is specifically configured to transmit applicationlayer protocol signaling to the access network equipment through thetransmiter, the application layer protocol signaling carrying theterminal device identifier of the remote terminal device.

Optionally, the receiver 910 is specifically configured to receiveapplication layer protocol signaling sent by the access networkequipment, where the application layer protocol signaling is sent by theaccess network equipment according to an RRC message sent by the relayterminal device, and the RRC message carries the bearer setup request.

In an optional example, the apparatus 900 may correspond to the corenetwork equipment in the above method embodiments, and may be configuredto perform each step and/or process corresponding to the core networkequipment in the above method embodiments. Optionally, the apparatus 900may further include a storage device. The storage device may include aROM and a RAM, and provide instructions and data to the processor. Apart of the storage device may further include a non-volatile RAM. Forexample, the storage device may also store information about the devicetype. The processor may be configured to execute the instructions storedin the storage device, and when executing the instructions stored in thestorage device, the processor performs each step and/or process in theabove method embodiments.

FIG. 12 shows another apparatus for relay transmission 1000 provided byan embodiment of the disclosure. As shown in FIG. 12, the apparatus 1000includes:

a receiver 1010, configured to receive a bearer setup request forrequesting the setup of an EPS bearer for a remote terminal device;

a processor 1020, configured to set up an EPS bearer for the remoteterminal device according to the bearer setup request received by thereceiver 1010, where the EPS bearer includes a cellular datatransmission channel between the access network equipment and a relayterminal device and a D2D data transmission channel between the relayterminal device and the remote terminal device; and

a transmiter 1030, configured to transmit a reconfiguration message tothe relay terminal device, the reconfiguration message carryingconfiguration information of the EPS bearer set up by the processor1020.

Optionally, the configuration information of the EPS bearer includesconfiguration information of a cellular communication interface betweenthe relay terminal device and the access network equipment andconfiguration information of a D2D communication interface between therelay terminal device and the remote terminal device.

Optionally, the configuration information of the cellular communicationinterface is specifically first configuration information of a physicallayer, and the configuration information of the D2D communicationinterface is specifically second configuration information of thephysical layer; or

the configuration information of the cellular communication interface isspecifically first configuration information of a physical layer andfirst configuration information of a Layer 2, and the configurationinformation of the D2D communication interface is specifically at leastone of second configuration information of the physical layer and secondconfiguration information of the Layer 2.

Optionally, the first configuration information of the physical layerincludes at least one of: information of a first transmission resourcefor relay transmission on the cellular communication interface, arelay-specific RNTI, a correspondence between a data volume interval forrelay transmission and a PUCCH resource, and a correspondence betweenthe data volume interval for relay transmission and a preamble, wherethe relay-specific RNTI is used by the access network equipment toscramble a PDCCH for scheduling downlink data transmission of the remoteterminal device.

Optionally, the second configuration information of the physical layerincludes: information of a second transmission resource for relaytransmission on the D2D communication interface.

Optionally, the first configuration information of the Layer 2 includesat least one of: a relay-specific LCID and a Layer-2 identifierallocated to the remote terminal device, the relay-specific LCID beingused for identifying relay transmission.

Optionally, the second configuration information of the Layer 2includes: the Layer-2 identifier allocated to the remote terminaldevice.

Optionally, the configuration information of the EPS bearer furtherincludes configuration information of a user-plane peer layer betweenthe access network equipment and the remote terminal device.

Optionally, the receiver 1010 is specifically configured to receive anRRC message sent by the relay terminal device, the RRC message carryingthe bearer setup request.

Correspondingly, the processor 1020 is specifically configured totransmit, through the transmiter 1030 to the core network equipmentaccording to the RRC message, application layer protocol signaling forrequesting the setup of a bearer for the remote terminal device.

Optionally, the receiver 1010 is specifically configured to receiveapplication layer protocol signaling sent by the core network equipment,the application layer protocol signaling carrying the bearer setuprequest.

Optionally, the bearer setup request carries a terminal deviceidentifier of the remote terminal device.

Optionally, the bearer setup request is further configured to requestthe setup of a PDN connection for the remote terminal device. In thiscase, the processor 1020 is further configured to set up a PDNconnection for the remote terminal device according to the bearer setuprequest. Correspondingly, the transmiter 1030 is further configured totransmit configuration information of the PDN connection to the relayterminal device.

In an optional example, the apparatus 1000 may correspond to the accessnetwork equipment in the above method embodiments, and may be configuredto perform each step and/or process corresponding to the access networkequipment in the above method embodiments. Optionally, the apparatus1000 may further include a storage device. The storage device mayinclude a ROM and a RAM, and provide instructions and data to theprocessor. A part of the storage device may further include anon-volatile RAM. For example, the storage device may also storeinformation about the device type. The processor may be configured toexecute the instructions stored in the storage device, and whenexecuting the instructions stored in the storage device, the processorperforms each step and/or process in the above method embodiments.

It should be understood that, in the embodiments of the disclosure, theprocessor may be a Central Processing Unit (CPU), and may also be ageneral processor, a Digital Signal Processor (DSP), an ASIC, a FieldProgrammable Gate Array (FPGA), or a programmable logic device, adiscrete gate, a transistor logic device, a discrete hardware component,and the like. The general processor may be a microprocessor, or theprocessor may also be any conventional processor.

During the implementation, the steps of each method may be performedthrough an integrated logic circuit of hardware in a processor orthrough instructions in the form of software. The steps of each methoddisclosed by the embodiments of the disclosure can be directly performedby a hardware processor, or by a combination of hardware in a processorand a software module. The software module may be positioned in astorage medium which is mature in the art, such as a RAM, a flashmemory, a ROM, a programmable ROM, an electrically erasable programmablememory, or a register. The storage medium is located in the storagedevice. The processor executes the instructions in the storage device,and performs the steps in each method together with hardware in theprocessor. The details are not repeatedly described herein for brevity.

It should be understood that, for brevity, the differences between theembodiments are highlighted in the description of the embodiments of thedisclosure, and reference can be made to each other for the identical orsimilar parts.

Persons of ordinary skill in the art may realize that, the steps of eachmethod and the units described in the embodiments of the disclosure canbe implemented with electronic hardware, computer software, or thecombination thereof. In order to clearly describe the interchangeabilitybetween the hardware and the software, steps and compositions of eachembodiment have been generally described according to functions in theforegoing descriptions. Whether these functions are implemented inhardware or software depends on specific applications of the technicalsolutions and design constraints. Persons of ordinary skill in the artmay use different methods to implement the described functions for eachspecific application, but such implementation should not be consideredto be beyond the scope of the disclosure.

Persons skilled in the art can clearly understand that, for convenienceand brevity of description, reference can be made to correspondingprocesses in the foregoing method embodiments for specific workingprocesses of the above-described systems, apparatuses, and units.Details are not described herein again.

In several embodiments provided herein, it should be understood that thedisclosed system, apparatus, and method may be implemented in othermanners. For example, the described apparatus embodiment is merely anexample. For example, the unit division is merely logical functiondivision and may be other division in actual implementation. Forexample, a plurality of units or components may be combined orintegrated into another system, or some features may be ignored or notperformed. In other respects, the intercoupling or direct coupling orcommunication connection shown or discussed may be indirect coupling orcommunication connection through some interfaces, apparatuses, or units;or may be implemented in electrical, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate. Parts displayed as units may or may not be physical units,which may be located in one position, or may be distributed on aplurality of network units. Some or all of the units may be selectedaccording to actual needs to achieve the objectives of the solutions ofthe embodiments.

In addition, functional units in the embodiments of the disclosure maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units are integrated into one unit. Theforegoing integrated unit can be implemented either in the form ofhardware or in the form of software functional units.

The integrated unit, if implemented in the form of a software functionalunit and sold or used as a stand-alone product, may be stored in acomputer-readable storage medium. Based on this understanding, thetechnical solution of the disclosure essentially, or a part contributingto the prior art, or all or a part of the technical solution may beembodied in a form of a software product. The computer software productis stored in a storage medium, and includes several instructions toenable a computer device (which may be a personal computer, a server, oran access network equipment) to execute all or some steps of the methodaccording to the embodiments of the disclosure. The foregoing storagemedium includes: any medium that can store program code, such as a USBflash disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or anoptical disc.

The above merely describes specific embodiments of the disclosure, butthe protection scope of the disclosure is not limited thereto. Anyperson skilled in the art can easily conceive equivalent modificationsor replacements within the technical scope of the disclosure, and thesemodifications or replacements shall fall within the protection scope ofthe disclosure. Therefore, the protection scope of the disclosure shouldbe subject to the protection scope of the claims.

1. A method for relay transmission, comprising: transmitting, by a relayterminal device, a bearer setup request to a core network equipment, thebearer setup request being configured to request setup of an EvolvedPacket System (EPS) bearer for a remote terminal device; and receiving,by the relay terminal device, a reconfiguration message sent by anaccess network equipment, the reconfiguration message carryingconfiguration information of the EPS bearer set up for the remoteterminal device, wherein the EPS bearer comprises a cellular datatransmission channel between the access network equipment and the relayterminal device and a Device-to-Device (D2D) data transmission channelbetween the relay terminal device and the remote terminal device.
 2. Themethod according to claim 1, before the transmitting, by the relayterminal device, the bearer setup request to the core network equipment,further comprising: receiving, by the relay terminal device, aconnection setup request from the remote terminal device, the connectionsetup request being configured to request setup of a D2D communicationlink between the relay terminal device and the remote terminal device;and wherein the transmitting, by the relay terminal device, the bearersetup request to the core network equipment comprises: transmitting, bythe relay terminal device, the bearer setup request to the core networkequipment according to the connection setup request.
 3. The methodaccording to claim 1, wherein the transmitting, by a relay terminaldevice, the bearer setup request to the core network equipmentcomprises: transmitting, by the relay terminal device, a Non AccessStratum (NAS) message to the core network equipment, the NAS messageresponding to the bearer setup request.
 4. The method according to claim3, wherein the bearer setup request carries the terminal deviceidentifier of the remote terminal device; and the EPS bearer is set upby the core network equipment transmitting application layer protocolsignaling to the access network equipment, the application layerprotocol signaling carrying the terminal device identifier of the remoteterminal device.
 5. The method according to claim 1, wherein thetransmitting, by the relay terminal device, the bearer setup request tothe core network equipment comprises: transmitting, by the relayterminal device, a Radio Resource Control (RRC) message to the accessnetwork equipment, the RRC message carrying the bearer setup request,such that the access network equipment transmits, to the core networkequipment according to the RRC message, application layer protocolsignaling for requesting setup of a bearer for the remote terminaldevice.
 6. The method according to claim 1, wherein the bearer setuprequest is further configured to request setup of a Packet Data Network(PDN) connection for the remote terminal device; the reconfigurationmessage further carries configuration information of the PDN connectionset up for the remote terminal device.
 7. The method according to claim6, wherein the method further comprises: transmitting, by the relayterminal device, the configuration information of the PDN connection tothe remote terminal device.
 8. A relay terminal device, comprising: atransmitter, configured to transmit a bearer setup request to a corenetwork equipment, the bearer setup request being configured to requestsetup of an Evolved Packet System (EPS) bearer for a remote terminaldevice; and a receiver, configured to receive a reconfiguration messagesent by an access network equipment, the reconfiguration messagecarrying configuration information of the EPS bearer set up for theremote terminal device, wherein the EPS bearer comprises a cellular datatransmission channel between the access network equipment and the relayterminal device and a Device-to-Device (D2D) data transmission channelbetween the relay terminal device and the remote terminal device.
 9. Therelay terminal device according to claim 8, wherein the receiver isfurther configured to receive a connection setup request from the remoteterminal device before the transmitter transmits the bearer setuprequest to the core network equipment, the connection setup requestbeing configured to request setup of a D2D communication link betweenthe relay terminal device and the remote terminal device; and thetransmitter is specifically configured to transmit a bearer setuprequest to the core network equipment according to the connection setuprequest received by the receiver.
 10. The relay terminal deviceaccording to claim 8, wherein the transmitter is specifically configuredto transmit a Non Access Stratum (NAS) message to the core networkequipment, the NAS message responding to the bearer setup request. 11.The relay terminal device according to claim 10, wherein the bearersetup request carries a terminal device identifier of the remoteterminal device; and the EPS bearer is set up by the core networkequipment transmitting application layer protocol signaling to theaccess network equipment, the application layer protocol signalingcarrying the terminal device identifier of the remote terminal device.12. The relay terminal device according to claim 8, wherein thetransmission unit is specifically configured to transmit a RadioResource Control (RRC) message to the access network equipment, the RRCmessage carrying the bearer setup request, such that the access networkequipment transmits, to the core network equipment according to the RRCmessage, application layer protocol signaling for requesting setup of abearer for the remote terminal device.
 13. The relay terminal deviceaccording to claim 8, wherein the bearer setup request is furtherconfigured to request setup of a Packet Data Network (PDN) connectionfor the remote terminal device; and the reconfiguration message furthercarries configuration information of the PDN connection set up for theremote terminal device.
 14. The relay terminal device according to claim13, wherein the transmitter is further configured to transmit theconfiguration information of the PDN connection to the remote terminaldevice.
 15. An apparatus for relay transmission, comprising: a receiver,configured to receive a bearer setup request for requesting setup of anEvolved Packet System (EPS) bearer for a remote terminal device; aprocessor, configured to set up the EPS bearer for the remote terminaldevice according to the bearer setup request received by the receivingunit, wherein the EPS bearer comprises a cellular data transmissionchannel between the access network equipment and a relay terminal deviceand a Device-to-Device (D2D) data transmission channel between the relayterminal device and the remote terminal device; and a transmitter,configured to transmit a reconfiguration message to the relay terminaldevice, the reconfiguration message carrying configuration informationof the EPS bearer set up by the processor.
 16. The apparatus accordingto claim 15, wherein the receiver is specifically configured to receivea Radio Resource Control (RRC) message sent by the relay terminaldevice, the RRC message carrying the bearer setup request; and theprocessor is specifically configured to transmit, through thetransmission unit to the core network equipment according to the RRCmessage, application layer protocol signaling for requesting setup of abearer for the remote terminal device.
 17. The apparatus according toclaim 15, wherein the receiver is specifically configured to receiveapplication layer protocol signaling sent by the core network equipment,the application layer protocol signaling carrying the bearer setuprequest.
 18. The apparatus according to claim 15, wherein the bearersetup request carries a terminal device identifier of the remoteterminal device.
 19. The apparatus according to claim 15, wherein thebearer setup request is further configured to request setup of a PacketData Network (PDN) connection for the remote terminal device; and theprocessor is further configured to set up the PDN connection for theremote terminal device according to the bearer setup request.
 20. Theapparatus according to claim 19, the transmitter is further configuredto transmit configuration information of the PDN connection to the relayterminal device.